Test Drove a Volt today

I said I would be burning little or no fossil fuel which, where I come from, would be true. Once again, your mileage may vary...although I still believe that EV can/will eventually lead to less emissions as the grid (or local) electricity generation becomes cleaner.

I agree it does depend where you live. Regardless, electric has the potential to become much cleaner. Burning fossil fuels does not.

Perhaps I am getting a little ahead of myself by making the statement that electric holds the promise of best efficiency. But I have to wonder how much better it will be when we have been using and refining the technology for as long and as much as we have the ICE. I still think it has the best efficiency potential.

Once again I never claimed that all electricity is zero emissions. I just said that I would be burning little to no fossil fuel. I was talking about my situation.

 

Do you have any charts that shows the energy used/pollution created to transport and refine crude oil into gasoline that is eventually burned by the Prius and how that comes into play? If we're going to compare how much pollution an electric car creates when it consumes it's energy source to create forward motion, shouldn't the pollution created by refineries, for example, that create that gallon of gas that a Prius converts into forward motion also be taken into consideration as well? Along with the transpiration of the crude and refined products from the ground to the gas station?

 

Figure 6.10 includes everything because it is the chart for WTW (well-to-wheel). This would take account of every emission from extracting oil from the well all the way to turning the wheels. Prius @50 MPG emits 243 gram/mile. The chart shows 270 gram/mile.

 

I posted this chart over at the Well-to-wheels analysis thread. A PHEV40 (like Volt) uses the same energy as a standard hybrid in CD mode but more in CS mode. You can check out more charts showing GHG emission and Petroleum usage in that thread.

The chart is missing pure EV so perhaps Leaf may do marginally better since it is lighter than the Volt by about 500 lbs.

 

Although often sited on Prius Chat and in news stories these past few months, it is worth noting that the Argonne Report of June, 2010, is an outlier when compared with the dozens of similar studies of well-to-wheel energy useage and greenhouse gas emissions. Please see my analysis for details.

https://sites.google.com/site/nwpri...eenhouse-gas-emissions-from-electric-vehicles

The 250 Wh/mile from the battery that is commonly used as a rule of thumb for vehicles driving on electricity is very close to the average of many studies and actual data. When corrected for the conversion losses (about 15%), the result is 294 Wh/mile of energy consumed from the grid, and the average from the sources I compiled is 286 Wh/mile.

As noted in my analysis, Argonne estimates in Table 3.3 (page 37) that energy useage for a mile of PHEV-20 driving will be 634 Wh, about 2.2 times the average that other studies and actual driving results combined indicate. Their too-high energy assumption leads them to forecast similarly inflated GHG emission results for PHEV’s.

NW BMS+ Driver

 

In Table 3.3, PHEV-20 energy usage for "CD Electric" is 755 Btu/mi. That is converted to 221.27 Wh/mi. How are you getting 634 Wh/mi?

[Edit]: I see your explanation on your site. You are adding 413 Wh/mi from "CD On-board". CD On-board is the engine fuel consumption in the blended CD operational mode. I believe they are taking account of all the BTU in the gasoline, not just the usable engine from gas engine. Atkinson cycle engine is at most 40% efficient so 165 Wh/mi is the usable energy from gasoline.

The other studies that you cited, does it take account of the wasted energy?

 

You misunderstand.

"250 wh/mile" as commonly quoted is transmission shaft to wheel rule of thumb.
"634 wh/mile" is a well to wheel estimate.

I find it kind of amazing that some otherwise intelligent people have trouble accepting that electrical devices are not GHG savers when the central power plant is no more GHG efficient than the distributed power plant. <shrug>

Personally, I promote EVs because they encourage consumers to bring more PV online.

 

"Regular Hybrid" has 806 Wh/mi for well-to-wheel also. 40% efficiency would put it at 322 Wh/mi. 31% efficiency would put it at 250 Wh/mi.

 

And 1% efficiency would put it at 8 wh/mile ?

 

Yes, and 798 Wh/mi is wasted. I think even a bicycle use more than 8 Wh/mile.

 

Just to follow up my other post.

The paper stated they used 85% efficiency for the electric due to the loss the charger and the battery. We can use 35% efficiency for the Atkinson cycle to be more realistic.

Usable Electricity energy: 221 Wh/mi x 0.85 = 188 Wh/mi
Usable Gasoline energy: 413 Wh/mi x 0.37 = 145 Wh/mi

The total came out to 333 Wh/mi which isn't far from the other numbers.

BTW, great work on putting together data from other reports.

 

Motortrend has been paid off to drool over the Volt. I have the magazine in front of me, and if you flip the cover over, you get... 2 pages of Cadillac advertisements, and later in the magazine, an 8-page Volt ad on card-stock paper. No ads for Toyota, Honda, or Nissan in the entire magazine. So of course Motortrend will say GM is better than Toyota. Pay me off, and I’ll lie too! That said, if the Volt were $12,000 cheaper, the PHV Prius would have some real competition. Oh well. GM CEOs need their yachts.

 

ok, now I am confused what you are trying to report.

If 221 wh/mile is the energy required at the wheels, and 15% of energy is wasted, then 221/.85= 260 wh/mile is the energy needed from the grid.

Or perhaps you are thinking of something else entirely ?

 

As an example, assume 200 wh/mile well-tank,
and 600 wh/mile tank to wheel for a total 800 wh/mile well-wheel.

If we say that the ICE has 33.3% efficiency and use that as a surrogate tank-wheel efficiency, then 200 wh/mile goes to the wheels.

From here I lose what you are trying to calculate. 33.3% of 800 is 266 -- but that value does not match any of the starting parameters.

 

221 Wh is the energy needed from the grid. My calculation is for the energy required to turn the wheels.

 

ok, but that sounds too low a number if meant to be realistic.

 

You are right. I see where I went wrong.

221 Wh from electricity is WTW so it includes everything starting from the well, generate electricity, transport it, charge the battery, to all the way to turning the wheels.

The same goes for 431 Wh from gasoline. The calculation I was doing is only for tank-to-wheel. You are right, I'll need to take out well-to-tank.

 

Sorry, I am still not following. 221 wh/mile well-wheel (WTW) is way too low. 800 wh/mile (whether EV or Prius) is closer to real world.

Anyway, mostly I was just pointing out that multiplying WTW energy/mile by motor or ICE efficiency gives a result, but I am not sure what that result is meant to convey.

 

Motor Trend also named the Chevy Vega "Car of the Year" when it came out. (which turned out to arguably be one of the worst cars ever made)

LOL

 

Sounds like a neat experience. Thanks for sharing your impressions.

At the end of the day, competition from the Volt will only improve the product from all brands, including Toyota. I doubt that Toyota will just cede its fuel economy and environmental leadership to the Volt without a fight. (And yes, I know that the Volt's tailpipe emissions aren't as clean as the Prius'.)